Design of a lower limb exoskeleton for experimental research on gait control

This paper presents the design of a modular lower limb exoskeleton intended for gait control research. The design requirements for this project will be presented as well as the solutions proposed to fulfill the purpose of the exoskeleton. More precisely, the exoskeleton will be used to measure the pseudo-impedance of the knee and ankle at specific instants during gait, such as heel strike and toe-off. It is intended to use these parameters in the control of powered prostheses, robotic exoskeletons or other devices working in parallel with the human body. In this work the details of the design of an innovative exoskeleton based on the modular concept is presented. The exoskeleton has two modes of operation (active and passive) that can be selectively applied to the knee or the ankle joints. The mechanical modularity can be easily extended to incorporate a hip joint. The design of the control strategy to measure the human pseudo-impedance will also be introduced. Finally, the preliminary tests using the exoskeleton in the passive mode including EMG will be presented.